Rolling mills

ABSTRACT

This invention is concerned with improved bearings for rolls of a rolling mill. According to the invention a pair of opposed rolls are supported in vertically adjustable hydrostatic bearing assemblies for resisting the vertical rolling force and separate means are provided to contain the horizontal forces. The hydrostatic bearing assemblies surround less than half the circumference of the roll barrels so that they can accommodate different sizes of rolls and do not need to be changed each time the rolls are changed or reground.

United States Patent 72] lnventor Harry Laurence Fred Bond Hathersage, near Sheffield, England [21] Appl. No. 664,120 [22] Filed Aug. 29, 1967 [45] Patented Mar. 23, 1971 [73] Assignee Davy and United Engineering Company Limited Sheflield, Yorkshire, England [32] Priority Aug. 31, 1966 [3 3] Great Britain [31] 38874/66 [54] ROLLING MILLS 2 Claims, 2 Drawing Figs.

[52] U.S. Cl 72/245, 72/244 [51] Int. Cl B2lb 31/32, B2lb 31/30 [50] Field of Search 72/237,

244, 200, 242; 308/9, 73, (lnquired), 5; 72/245 [56] References Cited UNITED STATES PATENTS 602,864 4/ 1898 Matthews 72/244 977,725 12/1910 Gautschi 72/200 1,519,657 12/1924 Biggert.... 72/245 3,031,872 5/1962 Kusters.... 72/245 3,169,423 2/1965 Sims 72/242 3,231,319 1/1966 Porath 308/5 Primary Examiner-Milton S. Mehr Attorney-Henry C. Westin ABSTRACT: This invention is concerned with improved bearings for rolls of a rolling mill. According to the invention a pair of opposed rolls are supported in vertically adjustable hydrostatic bearing assemblies for resisting the vertical rolling force and separate means are provided to contain the horizontal forces. The hydrostatic bearing assemblies surround less than half the circumference of the roll barrels so that they can accommodate different sizes of rolls and do not need to be changed each time the rolls are changed or reground.

PATENTEUmzansn SHEET 1 [1F 2 Haj;

INVENTOR HARRY L. E BOND HENRY ,C. WESTIN ATTORNEY 'PATENvTlinmzslsn 7 3572.079

' sncnanfz INVENTOR BY HARRY L. B

HENRY C...\NisT\N ATTORNEY ROLLING MILLS This invention relates to rolling mills and particularly to bearing means for rolling mills.

Conventionally rolling mills have the rolls supported b their necks in bearings, for example roller bearings, in roll chocks, which chocks are restrained against horizontal and vertical movement to maintain the rolls in a desired position. The roll barrels and the roll bearings are nominally coaxial; although a great deal of trouble is taken to make them as coaxial as possible, in practice eccentricity always arises causing a cyclic change in roll gap and a corresponding recurring error in the gauge of material produced. The error'introduced by eccentricity is very hard to eliminate by any known control system. 3

While it has been-previously proposed to support the rolls, preferably the backup rolls of a mill, by hydrostatic bearings acting on the roll barrel, in order to contain both the horizontal and vertical forces on the rolls, these bearings have previously been made to encircle the roll barrel over an arc exceeding 180 for example three-quarters of the circumference of the barrels. Suchbearings contain pads arranged to resist both the horizontal and vertical forces. It will be appreciated that a definite clearance between the hydrostatic pad of the bearing and the roll has to be maintained so that a fresh bearing must be fitted whenever the roll size is changed or as the roll surface wears. For example as little as one sixty-fourth of an inch change in diameter of a 20 inch diameter roll would be suffrcient to impair working of the bearings.

In a mill according to the present invention, a pair of opposed rolls are supported in hydrostatic-bearing assemblies necks supported in work roll chocks 105 and upper and lower backup rolls 106 have their necks supported in backup roll chocks 107. The chocks 105, 107 are supported in the housing windows 101 so that they are constrained against horizontal movement, but are free to slide vertically in the windows. Each backup roll 106 is supported against vertical loads in a hydrostatic-bearing assembly 108, surrounding only about one quarter of the roll circumference'The bearing assemblies 108 at the top and bottom of the mill are similar and only one will be described. I

Each bearing assembly 108 comprises three separate bearings 109 symmetrically spaced along the length of the roll.

Each bearing 109 comprises a bearing block 110 having a number of semicylindrical recesses; two such recesses symmetrically arranged on opposite sides of the vertical plane through the axes of the rolls are illustrated in the drawings. In each recess 111 is located ahydrostatic pad 112' having recesses 113 in their bearing faces'1 l4 arranged to be supplied with pressurized fluid through bores 115 in known manner. The hydrostatic pads 112 may be supported in the recesses. 111 hydrostatically, or a suitable low friction medium such as P.T.F.E. could be introduced, or alternatively a suitable pad of semiresilient material may be used as a connection between the hydrostatic pads and their hearing blocks 110, which would have just sufficient resilience to allow the pads to align surrounding less than half the circumference of the roll barrels to contain the vertical rolling forces, and separate means are provided to contain the horizontal forces.

Preferably the hydrostatic-bearing assemblies are vertically adjustable and with such an arrangement the same hydrostatic bearings can be used on rolls of different sizes. Preferably the hydrostatic-bearing assemblies are divided into a number of separate bearings along the length of the rolls, each bearing being individually vertically adjustable, for example by means pads may be adjusted to suit a roll periphery and then locked in position, until such time as a roll of different diameter is introduced or until the roll wear has become excessive. It will be appreciated that he hearing may comprise more than two pads if in certain circumstances this is shown to give more efficient encirclement of the roll periphery.

Instead of having each hydrostatic bearing formed of a number of separate bearings, the hydrostatic bearing may run the full length of the roll barrel. In this case the associated bearing block is also in one length. If this block is made suitably flexible in the vertical plane and supported as required at a number of points along its length by vertically adjustable devices then the block can be flexed to any desired shape.

One embodiment of mill, in accordance with the invention, will now be described, by way of example only, with reference to the accompanying drawings, of which:

FIG. 1 is a vertical section through one side of a rolling mill; and

FIG. 2 is a front view of the mill partly in section on the line Il ll of FIG. 1.

The mill comprises a pair of housings 100 having windows 101 and connected by an upper crosshead 102 and a lower crosshead 103. Upper and lower work rolls 104 have their themselves to the periphery of theirassociated roll. The upper surface of each bearing block is tapered and bears against a corresponding tapered surface of a wedge 116 bearing against the mill crosshead. Wedges 116 are independently horizontally adjustable by means of piston and cylinder assemblies 117 mounted on the mill crosshead.

Instead of having a number of bearing pads 112 along the length of the roll barrel, a single hydrostatic bearing may extend over the full length of the barrel, being carried in a single bearing block similarly extending along the barrel. This long bearing block may then be made flexible and supported in the mill housing at a number of points along its length by vertically adjustable devices similar to the wedges 116, so that the block and hence the associated roll may be flexed.

It will be appreciated that as the bearings 109 surround only a fraction of the roll circumference, always less than half, and the hydrostatic pads are adjustable in attitude, the bearings are able to accommodate different roll diameters as the rolls wear and are turned down. The bearing assemblies 108 contain only the vertical loads, the horizontal loads being contained through the chocks. The horizontal containment of the rolls can be achieved in many other ways, such as having adjustable idle rolls on the horizontal centerline of the roll'in question, which could be brought in to suit any roll diameter and contain it in any required position.

It should further be appreciated that by arranging a series of support points for each of the bearings, each of which points is separately vertically adjustable by means of its wedge 116 and piston and cylinder 117, the vertical position of each bearing 109 can be separately controlled to'control roll shape. in addition if all three wedges associated with one roll are moved simultaneouslythen the roll will be equally displaced in the vertical direction and this will provide a control of roll gap. Such control may be automatic. It will be appreciated that any form of adjustment can be used in place of the wedges such as hydraulic cylinders or screws.

Although the drawings illustrate a four-high mill, it will be appreciated that the invention can be applied to any configuration of rolls, and particularly, to a two-high mill. ln accordance with the provisions of the patent statutes. 1 have explained the principle and operation of my invention and have illustrated and described whatl consider to represent the best embodiment thereof.

1 claim:

1. A rolling mill comprising a pair of spaced-apart housings each defining a window, a pair of opposed rolls, roll barrels and roll necks respectively constituting parts of said rolls, bearing chock assemblies associated-with the roll necks, the

the rolls each pad having a concave surface cooperable with the associated roll barrel and defining three recesses positioned side by side on the surface and each arranged to receive pressurized liquid and to enclose a pocket of pressurized liquid in contact with the roll barrel.

2. A rolling mill as claimed in claim 1 wherein the bearing block of at least one of the hydrostatic-bearing assemblies is displaceable vertically. 

1. A rolling mill comprising a pair of spaced-apart housings each defining a window, a pair of opposed rolls, roll barrels and roll necks respectively constituting parts of said rolls, bearing chock assemblies associated with the roll necks, the assemblies being displaceable vertically in the housings but contained against horizontal movement, at least one hydrostatic-bearing assembly supporting each roll and surrounding less than half the circumference of the roll barrel of said roll to contain the vertical rolling forces, each bearing assembly comprising a bearing block defining a pair of part-cylindrical recesses, a part-cylindrical self-aligning bearing pad in each recess, the pads of each pair being arranged on opposite sides of and adjacent the vertical plane passing through the axes of the rolls each pad having a concave surface cooperable with the associated roll barrel and defining three recesses positioned side by side on the surface and each arranged to receive pressurized liquid and to enclose a pocket of pressurized liquid in contact with the roll barrel.
 2. A rolling mill as claimed in claim 1 wherein the bearing block of at least one of the hydrostatic-bearing assemblies is displaceable vertically. 